B14 Detection and serotyping of Orientia tsutsugamushi from the unfed larval trombiculid mite Leptotrombidium scutellare

Scrub typhus is a rickettsial disease caused by Orientia tsutsugamushi. It is transmitted to humans via infected chiggers (larva of trombiculid mite). Eschar is a characteristic feature for the diagnosis of scrub typhus and other mite or tick-borne rickettsiosis. Immunofluorescence Antibody (IFA) test is the gold standard for the diagnosis, and doxycycline is the drug of choice for treatment of scrub typhus. We present a case series of scrub typhus in three patients from South India. All three patients presented with high grade fever and IgM scrub typhus was positive status in all cases. Doxycycline 100 mg twice daily for 7 days along with supportive care was effective in all the cases. Serum creatinine levels dropped to normal and renal status of all patients improved well with antimicrobial treatment. Early diagnosis of the infection is necessary as the disease as it can have multiple system involvement and serious complications.

Download Full-text

Detection of Orientia tsutsugamushi in Novel Trombiculid Mite Species in Northern Tamil Nadu, India: Use of Targeting the Multicopy traD Gene

Journal of Medical Entomology ◽

10.1093/jme/tjab180 ◽

2021 ◽

Author(s):

John Antony Jude Prakash ◽

Kannan Kamarasu ◽

P Philip Samuel ◽

Renu Govindarajan ◽

Punitha Govindasamy ◽

...

Keyword(s):

Nested Pcr ◽

Tamil Nadu ◽

Scrub Typhus ◽

Specific Antigen ◽

Single Copy ◽

Mite Species ◽

The Novel ◽

Orientia Tsutsugamushi ◽

Potential Vector ◽

Trombiculid Mite

Abstract Detection of Orientia tsutsugamushi DNA in a trombiculid mite chigger species suggests that it might be a potential vector of scrub typhus in an endemic area. Over a period of 20 mo, 85 rats were trapped, 57 had chiggers that were identified by standard morphometric techniques. The chigger pools were assessed by performing PCR assays targeting fragments of the single-copy genes 56 kDa type-specific antigen gene (TSA56) by nested PCR and the 47 kDa (htrA) quantitative real-time PCR (qPCR). The novel traD SYBR green assay that detects a multicopy gene was also performed. In total, 27 chigger pools were positive by traD qPCR, of which only 7 were positive by 47 kDa qPCR and in 3 of these, 56 kDa gene was amplified by nested PCR. Orientia tsutsugamushi-specific DNA was detected in Ascoschoengastia spp., Schoengastiella ligula, Leptotrombidium rajasthanense, Leptotrombidium deliense, and Leptotrombidium jayawickremei chigger pools. Therefore, they could be potential vectors of scrub typhus in Southern India. The three 56 kDa sequences belonged to TA716 genotype and Kato genogroup. Further studies are needed to confirm these chigger species as scrub typhus vectors in Northern Tamil Nadu.

Download Full-text

Detection and serotyping of Orientia tsutsugamushi from the unfed larval trombiculid mite Leptotrombidium scutellare

Medical Entomology and Zoology ◽

10.7601/mez.53.65_1 ◽

2002 ◽

Vol 53 (2) ◽

pp. 65-72 ◽

Cited By ~ 2

Author(s):

Mamoru TAKAHASHI ◽

Hiroshi URAKAMI ◽

Hitoko MISUMI ◽

Shinichi NODA ◽

Susumu YAMAMOTO ◽

...

Keyword(s):

Orientia Tsutsugamushi ◽

Trombiculid Mite

Download Full-text

Exemplar Abstract for Rickettsia tsutsugamushi (Hayashi 1920) Ogata 1931 (Approved Lists 1980) and Orientia tsutsugamushi (Hayashi 1920) Tamura et al. 1995 emend. Hördt et al. 2020.

The NamesforLife Abstracts ◽

10.1601/ex.974 ◽

2003 ◽

Author(s):

Charles Thomas Parker ◽

Sarah Wigley ◽

George M Garrity

Keyword(s):

Orientia Tsutsugamushi

Download Full-text

Faculty Opinions recommendation of Approaches to vaccines against Orientia tsutsugamushi.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.718007531.793476094 ◽

2013 ◽

Author(s):

Daniel Paris

Keyword(s):

Orientia Tsutsugamushi

Download Full-text

Scrub typhus (Orientia tsutsugamushi), A rapidly spreading epidemic in Chennai - A standalone lab experience

International Journal of Bioassays ◽

10.21746/ijbio.2016.09.0021 ◽

2016 ◽

Vol 5 (09) ◽

pp. 4896

Author(s):

Sripriya C.S.* ◽

Shanthi B. ◽

Arockia Doss S. ◽

Antonie Raj I. ◽

Mohana Priya

Keyword(s):

Scrub Typhus ◽

Clinical Symptoms ◽

Clinical Manifestations ◽

Febrile Illness ◽

Orientia Tsutsugamushi ◽

The Past ◽

Igm Elisa ◽

The Mean ◽

Specific Symptoms ◽

Symptoms And Signs

Scrub typhus (Orientia tsutsugamushi), is a strict intracellular bacterium which is reported to be a recent threat to parts of southern India. There is re-emergence of scrub typhus during the past few years in Chennai. Scrub typhus is an acute febrile illness which generally causes non-specific symptoms and signs. The clinical manifestations of this disease range from sub-clinical disease to organ failure to fatal disease. This study documents our laboratory experience in diagnosis of scrub typhus in patients with fever and suspected clinical symptoms of scrub typhus infection for a period of two years from April 2014 to April 2016 using immunochromatography and IgM ELISA methods. The study was conducted on 648 patients out of whom 188 patients were found to be positive for scrub typhus. Results also showed that pediatric (0 -12 years) and young adults (20 – 39 years) were more exposed to scrub typhus infection and female patients were more infected compared to male. The study also showed that the rate of infection was higher between September to February which also suggested that the infection rate is proportional to the climatic condition. Statistical analysis showed that the mean age of the patients in this study was 37.6, standard deviation was 18.97, CV % was 50.45.

Download Full-text

Comparison of Lethal and Nonlethal Mouse Models of Orientia tsutsugamushi Infection Reveals T-Cell Population-Associated Cytokine Signatures Correlated with Lethality and Protection

Tropical Medicine and Infectious Disease ◽

10.3390/tropicalmed6030121 ◽

2021 ◽

Vol 6 (3) ◽

pp. 121

Author(s):

Alison Luce-Fedrow ◽

Suchismita Chattopadhyay ◽

Teik-Chye Chan ◽

Gregory Pearson ◽

John B. Patton ◽

...

Keyword(s):

Flow Cytometry ◽

T Cell ◽

Host Response ◽

Cd8 T Cell ◽

Cd4 T Cell ◽

Cell Populations ◽

Murine Models ◽

Orientia Tsutsugamushi ◽

Multicolor Flow Cytometry ◽

Interstrain Difference

The antigenic diversity of Orientia tsutsugamushi as well as the interstrain difference(s) associated with virulence in mice impose the necessity to dissect the host immune response. In this study we compared the host response in lethal and non-lethal murine models of O. tsutsugamushi infection using the two strains, Karp (New Guinea) and Woods (Australia). The models included the lethal model: Karp intraperitoneal (IP) challenge; and the nonlethal models: Karp intradermal (ID), Woods IP, and Woods ID challenges. We monitored bacterial trafficking to the liver, lung, spleen, kidney, heart, and blood, and seroconversion during the 21-day challenge. Bacterial trafficking to all organs was observed in both the lethal and nonlethal models of infection, with significant increases in average bacterial loads observed in the livers and hearts of the lethal model. Multicolor flow cytometry was utilized to analyze the CD4+ and CD8+ T cell populations and their intracellular production of the cytokines IFNγ, TNF, and IL2 (single, double, and triple combinations) associated with both the lethal and nonlethal murine models of infection. The lethal model was defined by a cytokine signature of double- (IFNγ-IL2) and triple-producing (IL2-TNF-IFNγ) CD4+ T-cell populations; no multifunctional signature was identified in the CD8+ T-cell populations associated with the lethal model. In the nonlethal model, the cytokine signature was predominated by CD4+ and CD8+ T-cell populations associated with single (IL2) and/or double (IL2-TNF) populations of producers. The cytokine signatures associated with our lethal model will become depletion targets in future experiments; those signatures associated with our nonlethal model are hypothesized to be related to the protective nature of the nonlethal challenges.

Download Full-text

Scrub Typhus and Molecular Characterization of Orientia tsutsugamushi from Central Nepal

Pathogens ◽

10.3390/pathogens10040422 ◽

2021 ◽

Vol 10 (4) ◽

pp. 422

Author(s):

Rajendra Gautam ◽

Keshab Parajuli ◽

Mythili Tadepalli ◽

Stephen Graves ◽

John Stenos ◽

...

Keyword(s):

Genetic Diversity ◽

Scrub Typhus ◽

Febrile Illness ◽

Acute Febrile Illness ◽

Limited Information ◽

Orientia Tsutsugamushi ◽

Health Measures ◽

Central Nepal ◽

Vector Borne

Scrub typhus is a vector-borne, acute febrile illness caused by Orientia tsutsugamushi. Scrub typhus continues to be an important but neglected tropical disease in Nepal. Information on this pathogen in Nepal is limited to serological surveys with little information available on molecular methods to detect O. tsutsugamushi. Limited information exists on the genetic diversity of this pathogen. A total of 282 blood samples were obtained from patients with suspected scrub typhus from central Nepal and 84 (30%) were positive for O. tsutsugamushi by 16S rRNA qPCR. Positive samples were further subjected to 56 kDa and 47 kDa molecular typing and molecularly compared to other O. tsutsugamushi strains. Phylogenetic analysis revealed that Nepalese O. tsutsugamushi strains largely cluster together and cluster away from other O. tsutsugamushi strains from Asia and elsewhere. One exception was the sample of Nepal_1, with its partial 56 kDa sequence clustering more closely with non-Nepalese O. tsutsugamushi 56 kDa sequences, potentially indicating that homologous recombination may influence the genetic diversity of strains in this region. Knowledge on the circulating strains in Nepal is important to the development of diagnostic tests and vaccines to support public health measures to control scrub typhus in this country.

Download Full-text